Fastener cap

ABSTRACT

A fastener cap includes a shank having a longitudinal hole with a closed first end and an open second end. The shank further includes at least one engaging section on an inner wall delimiting the longitudinal hole. The engaging section has an inner diameter smaller than that of a remaining portion of the longitudinal hole. The engaging section is engaged with threading of an exposed portion of a shank of a screw and thus shields the exposed portion of the shank of the screw. The closed first end of the fastener cap improves the rust-preventing effect for the screw.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a fastener cap. More particularly, thepresent invention relates to a fastener cap for covering an exposedportion of a fastener such as screw, bolt, etc.

2. Description of the Related Art

Screws and bolts made of steel or the like provide excellent fasteningeffect. However, the threaded shank of a screw or bolt is apt to rustdue to contact with air or water, resulting in damage in the threadingas well as getting stuck. As a result, the screw or bolt could not bedetached when desired. This is particularly true for the exposedthreaded portion of a headless screw or bolt.

FIGS. 1 and 2 of the drawings illustrate a conventional fastener cap 2for covering an exposed portion of a shank 11 of a screw 1. The fastenercap 2, generally made of plastic, is substantially a cylindrical memberwith a longitudinal through-hole 21, allowing it to be mounted aroundand thus protect the exposed portion of the shank 11 of the screw 1. Thefastener cap 2 has an inner diameter slightly greater than a diameter ofthe shank 11 for protecting the exposed portion of the shank 11 fromrusting due to contact with ambient air or moisture. The life of thescrew 1 can be prolonged accordingly.

However, the inner circumference of the fastener cap 2 and the outercircumference of the exposed portion of the shank 11 of the screw 1 haveno reliable engagement therebetween such that the fastener cap 2 is aptto be disengaged from the shank 11 of the screw 1. In a case that thediametrical dimension of the longitudinal through-hole 21 of thefastener cap 2 is precisely controlled to be in a small tolerance formating with the diameter of the exposed portion of the shank 11 of thescrew 1 for providing a firm engagement therebetween, a problem mightarise that, due to expansion and shrinkage resulting from temperaturechange, the longitudinal through-hole 21 of the fastener cap 2 becomesso small that the fastener cap 2 could not be mounted around the exposedportion of the shank 11 of the screw 1. Further, ambient air or moisturemay enter the fastener cap 2 via the open end of the fastener cap 2,resulting in undesired rusting.

SUMMARY OF THE INVENTION

A fastener cap in accordance with the present invention comprises ashank includes a longitudinal hole that includes a closed first end andan open second end. The shank further comprises at least one engagingsection on an inner wall delimiting the longitudinal hole. The at leastone engaging section has an inner diameter smaller than that of aremaining portion of the longitudinal hole. The at least one engagingsection is adapted to engage with threading of an exposed portion of ashank of a screw.

Since the first end of the fastener cap is closed, the exposed portionof the shank of the screw is well shielded from ambient air andmoisture. The rust-preventing effect is improved. Damage to the exposedportion of the shank of the screw resulting from impact is alsomitigated and/or obviated. Further, the inner diameter of the at leastone engaging section of the fastener cap is slightly smaller than thediameter of the exposed portion of the shank of the screw so that thetubular shank of the fastener cap is firmly engaged with the threadingof the exposed portion of the shank of the screw.

Preferably, the longitudinal hole of the fastener cap has a diameterslightly greater than that of exposed portion of the shank of the screw.

Preferably, the at least one engaging section includes an annular teeth.

Preferably, the at least one engaging section is substantiallytriangular in section.

Preferably, the fastener cap further comprises a head on the closedfirst end thereof.

Preferably, the at least one engaging section is formed on anintermediate portion of the inner wall of the tubular shank of thefastener cap.

Other objectives, advantages, and novel features of the invention willbecome more apparent from the following detailed description when takenin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a screw and a conventionalfastener cap.

FIG. 2 is a sectional view of the screw and conventional fastener cap inFIG. 1.

FIG. 3 is a perspective view, partly cutaway, of a fastener cap inaccordance with the present invention.

FIG. 4 is a perspective view, partly exploded, of a vehicle sideviewmirror and a fastener cap in accordance with the present invention.

FIG. 4A is an enlarged view of a circled portion in FIG. 4.

FIG. 5 is a sectional view illustrating use of the fastener cap inaccordance with the present invention with an exposed portion of a shankof a screw of the vehicle sideview mirror.

FIG. 6 is an exploded perspective view of a partially embedded screw andthe fastener cap in accordance with the present invention.

FIG. 7 is a sectional view of the screw and the fastener cap in FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 3, a fastener cap 4 in accordance with the presentinvention can be mounted around, e.g., an exposed portion of a shank 31of a screw 3 of, e.g., a vehicle sideview mirror 5. In this embodiment,the fastener cap 4 comprises a tubular shank 41 including a longitudinalhole 411. More specifically, the tubular shank 41 includes a closedfirst end 42 and an open second end 43. A head (not labeled) may beformed on the closed first end of the tubular shank 41.

The longitudinal hole 411 includes at least one engaging section 44 (twoin this embodiment) on an inner wall of the tubular shank 41 delimitingthe longitudinal hole 411. The tubular shank 41 has an inner diameter(i.e., the diameter of the longitudinal hole 411) slightly greater thana diameter of a shank 31 of a screw 3 to be covered. Each engagingsection 44 has an inner diameter smaller than the remaining portion ofthe longitudinal hole 411. Preferably, the engaging sections 44 areformed on an intermediate portion of the inner wall of the tubular shank41. In this embodiment, each engaging section 44 includes an annulartooth projecting radially inward from the inner wall of the tubularshank 41, and the engaging sections 44 are spaced along a longitudinaldirection of the tubular shank 41.

Referring to FIGS. 4, 4A, and 5, the fastener cap 4 can be mounted to ascrew 3 of a vehicle sideview mirror 5 via the open second end 43 of thefastener cap 4 for shielding an exposed portion of a shank 31 of thescrew 3. Since the inner diameter of the tubular shank 411 is slightlygreater than the diameter of the shank 31 of the screw 3, the exposedportion of the shank 31 of the screw 3 can be covered and thus shieldedby the tubular shank 411 of the fastener cap 4, preventing the exposedportion of the shank 31 of the screw 3 from rusting due to contact withambient air or moisture. Since the inner diameter of each engagingsection 44 of the fastener cap 4 is slightly smaller than the exposedportion of the shank 31 of the screw 3, the engaging sections 44 of thefastener cap 4 are engaged with the threading of the exposed portion ofthe shank 31 of the screw 3.

In the illustrated embodiment, the annular tooth of each engagingportion 44 is substantially triangular in section, which is particularlyuseful to bite into a thread groove (not labeled) of the exposed portionof the shank 31 of the screw 3, providing a firm engagement between theexposed portion of the shank 31 of the screw 3 and the tubular shank 41of the fastener cap 4, as shown in FIG. 5. Thus, the fastener cap 4 canbe easily mounted to the exposed portion of the shank 31 of the screw 3while allowing a firm engagement between the exposed portion of theshank 31 of the screw 3 and the tubular shank 41 of the fastener cap 4.

Since the first end 42 of the fastener cap 4 is closed, the exposedportion of the shank 31 of the screw 3 is well shielded from ambient airand moisture. The rust-preventing effect is improved. Damage to theexposed portion of the shank 31 of the screw 3 resulting from impact isalso mitigated and/or obviated.

Referring to FIGS. 6 and 7, the fastener cap 4 in accordance with thepresent invention can be mounted around an exposed portion of a shank 61of a screw 6 that is partially embedded in a concrete wall or theground. Similar to the use with the screw 3 of the vehicle sideviewmirror 5 in FIG. 5, the exposed portion of the shank 61 of the screw 6is well shielded by the fastener cap 4. Damage to the exposed portion ofthe shank 31 of the screw 3 resulting from impact is also mitigatedand/or obviated.

As apparent from the foregoing, the fastener cap 4 in accordance withthe present invention can be used to protect the exposed portion of theshank 31, 61 of a screw 3, 6 while providing a firm engagement withexposed portion of the shank 31, 61 of a screw 3, 6. Further,manufacturing of the fastener cap 4 in accordance with the presentinvention is easy and thus has a low cost, as it is unnecessary toprecisely control the diametrical dimension of the longitudinal hole 411of the tubular shank 41 of the fastener cap 4 to be in a small tolerancefor mating with the diameter of the exposed portion of the shank 31, 61of the screw 3, 6.

Although specific embodiments have been illustrated and described,numerous modifications and variations are still possible withoutdeparting from the essence of the invention. The scope of the inventionis limited by the accompanying claims.

1. A fastener cap comprising: a shank comprising a longitudinal hole,the shank further comprising a closed first end and an open second end,the shank further comprising at least one engaging section on an innerwall delimiting the longitudinal hole, said at least one engagingsection having an inner diameter smaller than that of a remainingportion of the longitudinal hole, said at least one engaging sectionbeing adapted to engage with threading of an exposed portion of a shankof a screw.
 2. The fastener cap as claimed in claim 1 wherein thelongitudinal hole of the fastener cap has a diameter slightly greaterthan that of exposed portion of the shank of the screw.
 3. The fastenercap as claimed in claim 1 wherein said at least one engaging sectionincludes an annular teeth.
 4. The fastener cap as claimed in claim 1wherein said at least one engaging section is substantially triangularin section.
 5. The fastener cap as claimed in claim 1 wherein thefastener cap further comprises a head on the closed first end thereof.6. The fastener cap as claimed in claim 1 wherein said at least oneengaging section is formed on an intermediate portion of the inner wallof the tubular shank of the fastener cap.